A May inspection of Baltimore’s Patapsco Wastewater Treatment Plant showed continuing failures to properly treat and dispose of solid waste, preventing the plant from filtering out pollutants to a level to be expected after millions of dollars of investments at the facility in recent years.

In a report dated May 18-21, the Maryland Department of the Environment laid out 18 steps that must be taken to bring the Wagner’s Point plant into compliance with environmental permits and regulations.

If that doesn’t happen quickly, department officials have already said the state may soon take over the second of Baltimore’s large wastewater plants. The Maryland Environmental Service, a quasi-state agency, took over operations of the Back River Wastewater Treatment plant in Dundalk in March.

Amid the ongoing problems at both plants, Blue Water Baltimore and the Chesapeake Legal Alliance said Thursday they plan to ask a federal judge to issue a temporary injunction compelling Baltimore, which owns both plants, to address the problems. The groups have an ongoing lawsuit, filed under the federal Clean Water Act, against the city in federal court.

Baltimore’s Department of Public Works did not immediately respond to a request for comment.

Alice Volpitta, who serves as the Baltimore Harbor Waterkeeper at Blue Water Baltimore, called the continued problems “unacceptable” given that both the Patapsco and Back River plants received more than half a billion dollars in money collected from Maryland residents’ sewer bills for work to upgrade treatment systems and reduce Chesapeake Bay pollution.

Nitrogen and phosphorus released from the plants is a significant contributor to many of the bay’s woes, not to mention the unsafe bacteria released along with them. The nutrients feed algae blooms that block sunlight from reaching underwater life and that deplete dissolved oxygen in the water when they die and decompose.

“We have pollution levels that are now higher than they have been in years; at Patapsco, the plant’s effluent monitoring data show levels closer to raw sewage than the world class treatment levels that the public and policymakers expected,” Volpitta said.